tmux keeps your agent alive, but not if you shut your laptop. Here is exactly where the line sits

The repo is here. tmux is a terminal multiplexer: it lets you open several terminals inside one window, move between them, and leave them all running in the background. It is not a new tool, it is a standard one that people working on servers have used for years.

What is extra below: why the most repeated claim is wrong, what actually happens when you shut the lid, why it does not run on Windows and how to run it there anyway, install commands verified at the source, the nine keys that cover daily use, the three things that will annoy you on day one, and the recipe for closing the lid that actually works.

When you run an agent in a terminal, the work is tied to that terminal window. Close the window, drop the SSH connection, or shut the terminal by accident, and the work goes with it. tmux steps in between: the process is now attached to the tmux server sitting in the background, not to the window. Close the window and the session keeps living.

The second benefit is splitting the screen. An agent writing code in one pane, tests in another, server logs in a third, you in the fourth. All in one window, all visible at once. When you work with an agent, this is noticeably more comfortable than flipping between tabs.

This sentence shows up in almost every tmux explainer and it sounds great. But tmux does not take the work off your computer, it only detaches it from the terminal window. The work still runs on your machine. If the machine stops, the work stops.

There is a scenario where the claim holds, but it has one condition: the work has to run on another machine, not your laptop. This is what tmux has actually been used for all along, long before agents existed.

The difference: your laptop is just a screen now. It closing, sleeping or losing Wi-Fi does not touch the work, because the work is not there. In this setup tmux is required, not decoration: the moment the SSH connection drops, the process you started on the server dies with it, and preventing exactly that is what tmux does.

# In PowerShell opened as administrator
wsl --install

# Restart the machine, open Ubuntu, set a username and password
# Then, in the Ubuntu terminal
sudo apt install tmux

The wsl --install command enables the required components, installs Ubuntu by default and asks for a restart. It works on Windows 11 or on Windows 10 build 2004 and above. If WSL is already installed the command just prints its help text, in which case skip straight to the second step.

# macOS
brew install tmux

# Ubuntu, Debian and WSL
sudo apt install tmux

# Fedora
sudo dnf install tmux

# Arch
sudo pacman -S tmux

The logic of tmux: you press Ctrl+b and release it, then press the command key. Not together, one after the other. Ctrl+b is called the prefix key in tmux and almost everything starts with it. The moment you see the dark bar at the bottom, you are inside a tmux session.

The word ajan here is just the name you give the session, use whatever you like. Naming is optional, but once you have three sessions you will want to know which is which. To see every key binding press Ctrl+b then the question mark, and q to leave that view.

None of these are bugs, they are tmux defaults. But running into them without warning makes it feel like the tool is broken.

First and most annoying: the mouse wheel does nothing. Mouse support is off by default in tmux. To scroll up you press Ctrl+b then the left square bracket to enter copy mode, move with the arrow keys, and press q to leave. This is the first wall you hit while trying to read a long stretch of agent output. The permanent fix is to turn the mouse on.

# Add this to ~/.tmux.conf
set -g mouse on

# To apply it right away in a running session
tmux source-file ~/.tmux.conf

Second: the split keys feel backwards. The percent sign splits the screen side by side, the double quote splits it top and bottom. tmux's own docs call these horizontal and vertical splits, but the names describe the direction of the dividing line, not how the panes end up sitting. There is no shortcut for remembering this, just try both once and see which does what.

Third: Ctrl+b clashes with some programs. Emacs and a few terminal tools use that combination themselves. tmux lets you change the prefix key through the prefix option in the config file. If you are not hitting a clash, leave it alone, the default is a good choice.